What is the difference between a frigate, cruiser, destroyer?

Factual Questions
21

IIRC HMS Warrior was classed as a frigate, but in her day she was the most powerful warship afloat.

22

That’s because she was only the third or fourth ship of her type in the world. There weren’t yet enough ironclads for “ironclad” to be a designation.

And I’m old enough to remember when the 2-hit ship was a destroyer, the second 3-hit ship was a cruiser, and there was no PT boat. I was very confused as a child when a USN destroyer made a stop in Cleveland on a goodwill tour, and it was much larger than the USS Cod (a WWII sub now moored as a museum in Cleveland).